Hot water supply systems are known in the conventional technology wherein hot water, produced by making use of a heat pump, is supplied to where it is utilized (hereinafter referred to as the “utilization side”).
For example, Patent Document I discloses a hot water supply system in which high temperature water at about 90 degrees Centigrade is produced in a single heat pump unit and then stored in a hot water storage tank. The high temperature hot water stored in the hot water storage tank is supplied to the utilization side. The hot water supply system of Patent Document I produces intermediate temperature water by heat exchange with high temperature water and supplies the produced intermediate temperature water to heat utilization equipment such as a radiator for floor heating.
In addition, Patent Document II discloses a hot water supply system in which high temperature water at about 90 degrees Centigrade and intermediate temperature water at about 60-80 degrees Centigrade are separately produced in a single heat pump unit. The hot water supply system of Patent Document II supplies the produced high temperature water to the utilization side while supplying the produced intermediate temperature water to heat utilization equipment such as a radiator for floor heating.    Patent Document I: JP 2003-056905A    Patent Document II: JP 2002-364912A